P0087

CIRCUIT DESCRIPTION
The Engine Control Module (ECM) monitors Fuel Rail Pressure (FRP) using the fuel rail pressure sensor. If the sensor indicates a pressure less than the commanded rail pressure plus a possible transitional overshoot, the ECM will set Diagnostic Trouble Code (DTC) P0087 for fuel rail pressure too low.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0192, P0193, or P1635 are not set.
^ The ignition is ON.

CONDITIONS FOR SETTING THE DTC
The actual fuel rail pressure is less than 0.0 MPa at 0-400 RPM.

OR

The actual fuel rail pressure is less than 22.5 MPa at 600-4,000 RPM.

OR

The actual fuel rail pressure is less than 30 MPa at over 4,000 RPM.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS
A restricted fuel supply line may cause DTCs P0087 and P0093 to set at the same time. Refer to Fuel System Diagnosis. Component Tests and General Diagnostics

TEST DESCRIPTION

Steps 1-13:

The numbers below refer to the step numbers on the diagnostic table.
2. If the engine starts, there is adequate fuel pressure. A restriction in a fuel line or a sensor fault exists.
6. If the fuel rail pressure is above 23 MPa, there is adequate pressure at this time.
7. An open in the fuel rail pressure sensor circuit will cause the ECM to show the maximum reading of over 175 MPa.